"I think the big thing is [voters] are seeing a lot of fight," he told ABC News' George Stephanopoulos, adding that his double-digit victory in Michigan was a "monster win."

Trump also said he would change his style, which many have called bombastic and crass, after the primaries.

"I think they’re going to see a very different person when this is all over with," he said. "I was hit very hard by Marco [Rubio], and I had to hit him back harder."

Trump also won the Hawaii caucuses, while Sen. Ted Cruz scored a victory in Idaho.

Ohio Gov. John Kasich, also on "Good Morning America" this morning, said he was happy with his finish in Michigan, placing third behind Cruz with roughly 24 percent of the vote.

"We’re going to win in Ohio," he said. "That’s going to be a whole new ball game."

Kasich, who has yet to win a state, had the support of four in 10 late-deciding voters in Michigan.

"For the first time, people are starting to hear what I have to say," he said. "We’ll competing all across the Midwest. We’re still standing."

Republicans in Ohio and Florida will cast their votes for the candidates next Tuesday. But a CNN/ORC poll released this morning shows Trump maintaining a slight lead over Kasich in Ohio and a substantial lead over Rubio in Florida.